TY - JOUR
T1 - Broadband Infrared Spectroscopy of Molecules in Solutions with Two Intrapulse Difference-Frequency-Generated Mid-Infrared Frequency Combs
AU - Han, Noh Soo
AU - Kim, Junwoo
AU - Yoon, Tai Hyun
AU - Cho, Minhaeng
N1 - Funding Information:
M.C. thanks Taka for stimulating discussion over the past decades. We thank Dr. So Hyeong Sohn for helping us to prepare a supplementary cover image. This work was supported by the Institute for Basic Science (IBS) in the Republic of Korea with Grant No. IBS-R023-D1.
Publisher Copyright:
©
PY - 2021/1/14
Y1 - 2021/1/14
N2 - Mid-infrared (mid-IR) spectroscopy is an incisive tool for studying structures and dynamics of complicated molecules in condensed phases. Developing a compact and broadband mid-IR spectrometer has thus been a long-standing challenge. Here, we show that a highly coherent and broadband mid-IR frequency comb can be generated by using an intrapulse difference-frequency-generation with a train of pulses from a few-cycle pulse Ti:sapphire oscillator. By tightly focusing the oscillator output beam into a single-pass, fan-out-type periodically poled lithium niobate crystal and tilting the orientation of the crystal, we show that a mid-IR frequency comb with more than an octave spectral bandwidth from 1550 cm-1 (46 THz) to 3650 cm-1 (110 THz) and vanishing carrier-envelope-offset phase can be generated. Using two coherent mid-IR frequency combs with different repetition frequencies, we demonstrate that a broadband mid-IR dual-frequency comb spectroscopy of aromatic compounds or amino acids in solutions is feasible. We thus anticipate that researchers will find our mid-IR frequency combs useful for developing ultrafast and broadband linear and nonlinear IR spectroscopy of chemically reactive or biologically important molecules in condensed phases.
AB - Mid-infrared (mid-IR) spectroscopy is an incisive tool for studying structures and dynamics of complicated molecules in condensed phases. Developing a compact and broadband mid-IR spectrometer has thus been a long-standing challenge. Here, we show that a highly coherent and broadband mid-IR frequency comb can be generated by using an intrapulse difference-frequency-generation with a train of pulses from a few-cycle pulse Ti:sapphire oscillator. By tightly focusing the oscillator output beam into a single-pass, fan-out-type periodically poled lithium niobate crystal and tilting the orientation of the crystal, we show that a mid-IR frequency comb with more than an octave spectral bandwidth from 1550 cm-1 (46 THz) to 3650 cm-1 (110 THz) and vanishing carrier-envelope-offset phase can be generated. Using two coherent mid-IR frequency combs with different repetition frequencies, we demonstrate that a broadband mid-IR dual-frequency comb spectroscopy of aromatic compounds or amino acids in solutions is feasible. We thus anticipate that researchers will find our mid-IR frequency combs useful for developing ultrafast and broadband linear and nonlinear IR spectroscopy of chemically reactive or biologically important molecules in condensed phases.
UR - http://www.scopus.com/inward/record.url?scp=85099104657&partnerID=8YFLogxK
U2 - 10.1021/acs.jpcb.0c09595
DO - 10.1021/acs.jpcb.0c09595
M3 - Article
C2 - 33325228
AN - SCOPUS:85099104657
SN - 1520-6106
VL - 125
SP - 307
EP - 316
JO - Journal of Physical Chemistry B
JF - Journal of Physical Chemistry B
IS - 1
ER -